Battery:Built-in 400mA lithium battery,charging 2 hours,last for 5hours. Plug and Play Head Mic:It will automatically connect when power on. If it does not connect successfully, please reconnect as follows:1? Turn off the receiver and transmitter. 2?Turn on the transmitter, blue light is on, long press “+ ” to blue light flash. 3?Turn on the receiver immediately (There is no need to wait for the transmitter's blue light to stop flashing) wait for the connection. 4?The blue lights of both transmitter and receiver stop flashing, means connection is successful. Compatible Devices and Application:The wireless mic compatible with Voice Amplifiers,Multimedia equipment,Speakers with Mic input jack.It's ideal for class teaching,lecture,conference,also a very pop fitness headset mic. Professional Wireless Microphone Headset: Built-in condenser microphone, high sensitivity pickup and prevent howling, provide you with HD sound quality.?Adopt the latest UHF wireless technology provides a stronger signal , reducing the possibility of interference from Bluetooth or WiFi. Upgraded Head Microphone: wireless microphone headset with LED Display,it can be clearly displayed the frequency,volume and battery status.?Up to 165 feet transmission range in an open areal.?Support 40 sets to use at the same time. Not Support Mobile phone/Macbook/Laptop.